Brian Boru - King of Munster

After Brian’s brother Mahon was killed by Ivar of Limerick in 978, in a treachorous plot involving sevaral Gaelic Chieftains, he succeeded in establishing himself as King of Munster and wasted no time taking to the field to seek revenge for his brother’s death. In 978 on Scattery Island he faced the Viking King of Limerick Ivar in single combat and was victorious. He went on to defeat the Vikings in  the Battle of Bealach Leachta, This was his first major defeat of the Vikings and put him in contention for the position of High King of Ireland.  

During this time another great leader was rising in the north, Mael Sechnaill mac Domnaill (Malachy the Ui Néill King of Tara). Mael Sechnaill became High King when he defeated a Norse army and took control of Dublin in the Battle of Tara in 980. Traditionally the southern and northern Uí Néills had shared the title of High King for several hundred years. As Brian was growing in strength in the South, Mael Sechnaill mac Domnaill was growing in strength in the North, and a clash between them was inevitable. Eventually in 988 both men met and agreed to divide the rule of Ireland into two. Mael Sechnaill became King of the North and Brian Boru became King of the South of Ireland.  

Thereafter in 999 was the Battle of Glen Mama in Wicklow. Brian Boru (Bryan Boru) and the High King of Ireland, Máel Sechnaill, defeated the armies of Viking Dublin, led by Harald, and Leinster, led by Mael Morda. With their combined forces they defeated the Dublin Danes, and killed their leader Harold, son of Amlaf. and captured the King of Leinster. Bryan, marching to Dublin, went on to defeat his own stepson, Sitric Silkenbeard, (from his marriage to his mother Gormlaith) King of Dublin and brother to Harold. The city was burnt, prisoners and treasure were taken, and Sitric expelled. By now the Danish presence in Dublin and beyond was under serious threat.

Brian Boru becomes High King of Ireland

It was also at this time that Mael Sechnaill saw his star subside and that of Brian Boru rise to the ultimate seat of power. Previously they had worked together, Mael Sechnaill ruling the North and Brian ruling the South, and facing down and looting the Danish strongholds together. But Brian Boru had grown stronger and set about to assert his control over the whole island. It is said Malachy was given a year to restore his credit, but annalists differ in their telling of his fall. It is no surprise the annals of the south depicting Brian as a hero and Mael Sechnaill as deserving of his defeat! However the career of Mael Sechnaill has shown that he was a formidable warrior and leader and had enjoyed much success in the lead-up battles toward the end of the Viking Age in Ireland.

Rock of Cashel

By 1002, Máel Sechnaill II finally submitted to Brian Boru. The Uí Néill King, Mael Sechnaill mac Domnaill was apparently abandoned by his Northern kinsmen who now acknowledged Brian as High King of Ireland thus ending the several-hundred year reign of the Ui Néill Kings.

Brian Boru was crowned High King of Ireland in 1002 at the capital of the ancient kingdom of Munster, the Rock of Cashel.

Boru as High King

Brian Boru was crowned High King of Ireland in 1002 at the capital of the ancient kingdom of Munster, the Rock of Cashel. Previously the clan from south Munster, the powerful Eóghanachta had ruled from Cashel and the region and were powerful because of connections and the lands they ruled over. They were a largely peaceful clan, and so now were no threat to Brian.

Brian Boru ruled between Cashel and his native home of Killaloe after being elected High King and was instrumental in bringing prosperity and law and order to the country while holding the Vikings at bay. On becoming King of all Ireland Brian was given the name Boru, or Brian of the Tribes, as he collected tributes from all the subjected clans. He used these new resources to rebuild and furnish desecrated monasteries, found new churches such as Inis Cealtra and Killaloe. He also restored libraries and schools that had been burnt by the Vikings. In the second decade of the 11th century, the Vikings began to assert themselves once again and raided Irish settlements.

Brians’s descendants ruled from Cashel for one hundred years after his death when Murtagh O’Brien in 1101 gave the Rock of Cashel to the Catholic Church and it began to thrive as a Cathedral.

Brian Boru and the Law of Fixing Surnames

As well as the restoration and building works that were undertaken under the rule of Brian Boru, he also instigated many useful laws. The most significant and certainlt the most enduring was the one for fixing surnames.

Surnames had been generally introduced in Europe in the 10th, 11th and 12th centuries and they usually took names from places or titles. In Ireland these names were derived from the ancestor or originator of their particular clan. Such names were then given to the lands or chieftainships they held or ruled over.

Though a system of names of course existed they became obligatory under Brian's rule. The ancestors name was selected and the prefix O or Mac was added, meaning 'grandson of' or 'son of', like O'Brien or MacCarthy.

See our section on Clans of Ireland to learn more about family surmanes, and where they originated.

Surnames, clan titles

Brian Boru's Last Battle at Clontarf 1014

Brian Boru (Bryan Boru) and his clan the Dal gCais had been fighting the Vikings since his youth.  Even now there was continued unrest in Ireland at this time due to the shifting alliances between Irish Clans and Vikings. It is said that the Danes continued to host into Meath, encouraged by Mael Mordha, who had been slighted by the family of Boru. This challenge to  the power of Mael Sechnaill came to a head when his son Flann was killed in a skirmish at Howth in 1013. Brian agreed to support Malachy and sent an army to Leinsterwhere it is said they plundered "from Glendalough to Kilmainham". Brian himself reached Dublin and camped there for several months in anticipation of a battle. By winter this did not look likely so he returned south until the following spring.

The Danes also were preparing for battle and mustering support from as far away as Norway, and the Baltic Islands. Following thier success in Britain, as Sweyn was named King of England in this year, followed by Canute in 1017, they no doubt saw this as an opportunity to strike a blow to restore their power and even claim Ireland for themselves. As many Vikings came to Ireland with their families permanent residence in a new Viking colony, which they had inhabited for over two hundred years, was presumably anticipated. Their raids into Leinster continued as did their preparations for a final showdown with the High King and his supporters.

The Fierce Battle Ground

By April the Danes and Leinstermen had mustered 21,000 men, and MaelMorda was ready to challenge Brian and his troops to meet on the plains of Moynealta, at Clontarf. The Battle of Clontarf, took place on Good Friday, the 23rd of April, 1014 at dawn, when Brian and his armies faced the forces of Leinster and Viking Dublin. It was described by annalists as "a spirited, fierce, violent, vengeful and furious battle" where the heavily armoured Vikings and their Leinster and Norse allies were roundly defeated by Brian Boru and his men bearing battle-axes, spears and daggers. The losses on both sides were enormous and vary from "ten hundred in armour" to seven thousand a side.

The greatest tragedy of all was the fall of the victorious leader, and High King of Ireland. Brian Borumha (Bryan Boru) was killled in his tent, with his young nephew, by Brodar, a sorcerer-king from the Isle of Man. Although Brian had won the greatest victory of his career, he did not live long to enjoy it.

This battle and its hero, though there were many, rose quickly to mythic status, and is even remembered in Norse legend and song as "Brian's Battle".